Saw-blade holder



Aug. 20, 1935. a J BLUM 2,011,611

SAW BLADE HOLDER Filed Oct. 9, 1930 Patented Aug. 20, 1935 SAW-BLADE HOLDER George J. Blum, Chicago, 111.; assignor toiArm strong-Blum Mfg. 00., Chicago, 11]., a oorporation of Illinois Application October 9, 1930. Serial No, 487,432

The inventionrelates generally to saw-blade holders and more particularly to a saw-blade jAnother object is to provide a holder of this i character which permits a slight yielding or springing of the blade in a direction opposite to the directiono-f feed in order to hold the blade at an even pressure against t ework and which is arranged to augment the force exerted by the springing of the blade. V

A further object is to provide a holder ofthis character which securely holds-the blade in place,

in which a blade may-be readily secured in a minimum of time, and which is simple and inc);- pensive to construct. I V I Still another object is to provide a holder which, if the blade should break and-the broken end should jam against the workpiece, is free to slide to an out-ofthe-way position so that no other parts of the holder or sawframe will be broken. r it Other objects and advantages will become, apparent from the following: description taken in connection with the accompanyingdrawin in which: Figure 1 is a side elevation of a saw-blade holder embodying the features of my invention. 7 Fig. 2 is an enlarged side elevation of a portion of the holder shown in Fig. 1. v Fig. 3 is a vertical section taken along the line 3-3 of Fig. 2. r

Fig. 4 is a view similar toFig. 1 ofa modified form of holder.

Fig. 5 is a side view of the clamping screw.

Fig. 6 is an enclview of the clamping screw, W-hile the invention is susceptible of various modifications and alternative constructions, 'I have shown in the drawing and will herein describe in detail the preferred embodiment and a modified form thereof; but it is to be understood that I do not thereby intend to limit the inven-. tion to the specific forms disclosed, but intend to cover all modifications and alternative. construe: tions falling. within the spirit and scope of the invention as expressed in the appended claims.

A saw-blade holder embodying thefeatures or the invention, is adapted for, holding hack-saw blades used in power driven sawing machines, and comprises'in general a U-shaped frame It! which is adapted to. be reciprocated,and means attached to the ends of the respectivelegs H o! 7 Claims. (01. 29-73) thef rame lll for attaching the ends of a saw-. blade 13 thereto quickly and efiectually and in a manner such-as to prevent chatter.

In the? present embodiment of the invention. the ends of the legs I] are provided with alined apertures l2 in which a pair of blocks are respectively inserted for securing the saw-blade l3 thereto withthe cutting edge of the blade parallel to the direction of reciprocetiomthe blocks being attached to the ends of the blade and held against movement relative thereto other, than pivotal movement in the plane ofthe blade.

designates the block for securing the rep, endof the blade to one leg H of the frame. This block fits snugly within the aperture I2 in that leg, and loasa threaded hole in its outer end adapted to receive ascrew l5 which extends out wardly beyond the outer face of theleg I l and has aznutl6. and washer ll the eon, the latter abutting against the outerv race of the leg I I. Thus, when the block 14 is secured to the rear end of the blade and the front end of the blade is secured to the other lee H, the blade maybe placedunder tension by tightening the'nut "it;v An, important feature of the invention resides in the mountingof the front endoi-the blade so as to permit slight, pivotal-movement and thus take advantage ote yieldingof the blade-tor ,Cushioningpurposes during the firstipart of the cu ti g stroke.

To this end, in the prefcrrediorm of the invention shown in Figs, 1, 2 and 3, a sec-. .ondiblock 2B is mountedin the aperture I2 in said le lncthe outer end of the block 20, avpin 21 is mountedv with its axis transverse to the plane of the blade, the pin extending beyond both side faces of the block 211. The pin 2| is constructed to support the blockzil pivotally inthe leg II for movement in the plane of the bladeand for this purpose. fits into a notch 2.2 out across the outer .iaceoitheleg-H. r i r In 'this embodiment (Fig, ,1) the pin 2| is mounted below the line of tension of. the. saw blade, which lineoi, tension extends through the points of attachment of the blade to the blocks lliand 20, so that a line from the pin 21 to the point oiattachment ofthe hladeto the block 20 forms a downwardly, opening an le with the line of tension cfthe blade, the point of attachment of the blade to the block Zllbeing thevertex of said angle. To permit a pivotal movement, of the block 20 about the pin 2], the upper wall of the aperture l2 which receives the blockzll is tapered as at 23. .11.? Means are provided for closin the gaps be tween the block '20 and the upper and lower walls of the aperture 1 2 when the block is pivoted,

. means comprises a pair of closure blocks 24 slidably mounted for vertical movement in slots, cut

which across the upper and lower edges respectively of the block 20. A pin 25. extends vertically through the closure blocks 24' centrally, thereof and through a vertical holeinthe block 20. Surrounding the pin $5,, is a compression spring" 26 ssinefid 'w tq o ti s-ensu e b ocks 24 and urging them into contact with the adjacent walls of the aperture l2. Thus, the;-

'closure blocks "24 willremain' in contact with the walls of the aperture I2 for all'positiofi'sof pivotal movement of the second block z lrall lhe gaps between the block 20 aniwall qfi fihfipe f ture' l2 will be kept closed.

In theoperation of the preferhed form oii 'the device shownin Figs. 1, 2 and 3; when the bladeisbrought into cutting relation with the work,;;th e downward feeding pressure o fthe sawing machine on the blade will cause the front end" of fth'f blade to spring upwardly to aslighteXtentfsiichbpring ing movement ein'g permitted byigthe pivotal mounting off the block v If' th we're-theme with the line f tension the blade,"

. the tehsiOn bf-the blaid'e: wouid a oid e e'er'tam' v 1 t t .5

r ist'ance to any upvvardspringing "o r-{the front end iofthe: blade, battyacing -the m below the linebf-tension r the blade,"the resistance to upwar springin'g of he r nt end'ofthe blade'is increaseddiie to; the a gle-hetweeh ehne eimhg th pin 2 I and th'e pemt' eretteehment: tgt e' blade to theble kgue d he line d'f 'tnsion ofthe.

blade. pivotal mounting of"; the blade" pno= duces a' cushioning; effect" durihg'thre first part or the cutting stroke; which; it h prven'ts'chattering of th ationofsawingt 'On ac'oount'ofth tapered wall 0 the aperture l-Z iIithe leg supporting the rrent en ett e blade;

Bull tha'closuref'blocks 2 4 etfe ctively iirevent; th

' entrance of "sueh chips ordir't in theap'ertiirei n'the 'rnodified form of hblder s hown in Fig 4, Qunliing sim'ilarf'i roaderespe ts to that e theafiltstafdr block so, a pine i; extendin transveis iy'tb the plane 'of the blade eyond 'the eider ee "of 'lthe of the front f end of the -bIadeis -"similar to that shown?in: th'e first form ih -that the tensioh o'f'the :blatlais utilized to prevent chatter by producing a:cushioningefiectz But,'= -as the'ipivot" pin 31 is on the ilineaof tension'io'fithe bladexth: spring 313 isiintroduced'toaugmentg the downward pres'sure due it'o the tensioncof the :blade wheri th front end of the b1ade is 'sprung upwardly," and any chatter is thus eliminated. i

- *Forfcl'amping the blade l 2 .i'n1 the blocks 14 2t ahdast; the sameram or "structure is usdli zall 1 em my'e" "and eme.-

e action onejaw, a screw 4| is transversely threaded,

which screw has a pin 42 (see Figs. and 6) extending through a hole in the blade and into a hole 43 inthe other jaw. The inner end of the screws abutsfagainst the blade-and clamps it;

against the, pinjgrecfeiving jaw, 1 Thus, tightening the screw tends to force the jaws apart and the 3 natural spring of the metal assists in the clamping t n, r r it "Top'r'ov'ide, a smooth seat on the inner end of tthescrewfll to abut against a substantial area on I the b adeaiioimd the hole, the portion of the inner end ofathejscrew -immediately surrounding the pin 42% is relieved asat M to forman annular seat 45 radially spac'e'cl from the pin and adapted to bear; against the blade when the screw is tightened in the block. v Thus, clamping er the blade about the hole tends to revent shearing-of the bladeQ blade may occur and, in the reciprocation of thesaw frame after such breakage, the'brokenefidof the 'blade;may ja'rna'g'ain'st the workpiece with s'u'c h force' that further damage may-teem such as breakage of the' blade holder or of cheer the arms of the saw frame. To avoid this diffi'culty, the blade holderis made in-s'u'ch'amanner' as to be'freely slidableto an out-of-the-way'position when the -blad is broken. To'this end, thescrews 4| are o f 'such' character-that they' 'lie entirely within the cross-sectional area of the blocks 14, 29 or and do notextend beyo'n'ol the side faces thereoflas is shown 'in'Fig. 3'. Thus,should the brokenend of abl'adejam against the work piece, the blocks are free to slide outwardly throughthe aperturest2 'inthe legs I I of the saw frame without interference of the screws-4i with the legs I I I have provided a novel saw-blade holder which, while preventing; chatter; securely holds the blade in' plalce,and -in' which a "blade may bereadily secured in'amihimum of time; It is alsoapparent that the holder is simple and inexpensive to contructf'mt I J -"I' claim as myinvention:-- I r I "-1.;Afsaw-bladeholder for-hacksawmachines comprising, in combination, a carrier, and means 'for" rnounting the ends of ablade in the carrier 1 andoperable toplace the bladeunderfa normal predetermined;tension. lengthwisethereof, said means having a slight pivotal movement of the forward end'of-theblade-about a pointoffset toward the work piecefrom the lin e ot'tension of the" blade tdinc're'ase'the tension of the blade as an incident to its application to a pieceof 'work.

2. A saw-blade holder comprising, in combina- 'tion',' a" U shaped frame, 'asaw blade," means for securing the rear end of the blade to one leg of the frame, and a block securedat one end to the front-end ofthe "blade againstmovement rela'' tive' thereto other than I pivotal movement and pivotedat its other endxto the other legofthe frame-on an'a'xis transverse to-theplane of the blade;'-s'aid axis' bein'g; belowthe line of tension of the blade to increase the force- -necessary' to sprin the-front endaof" the blade "upwardly. e I 3.- 'A"-'sawblade holder comprising-, in combina tion, a Uf-shaped frame havingaline'ol apertures in-th'eendsof the respective legs of the frame, a saw-blade, means for se curingthe' rear end 'of the blade tol one leg of 'the frame,' a block se-' cured to the front 1 endfof the blade and within theaperture in the otherleg of "the' -frameand From the above" description; it is app'arentthat 5 1 securing the rear end of the blade to one leg of the frame, a block secured to the front end of the blade and extending through an aperture in the other leg of the frame, a pin pivotally supporting said block in said aperture and mounted adjacent the outer end of said block on an axis transverse to the plane of the blade, the aperture receiving said block being tapered to permit pivotal movement of the second block in the plane of the blade when the blade is sprung upwardly, and means for closing the gaps between said block and the walls of the aperture comprising a pair of closure blocks slidably mounted respectively in the opposite edges of the second block and a compression spring mounted within said second block and urging said closure blocks outwardly against the adjacent walls of the aperture.

5. A saw-blade holder comprising, in combination, a U-shaped frame having alined apertures in the ends of the respective legs of the frame, a saw-blade, means for securing the rear end of the blade to one leg of the frame, a block secured to the front end of the blade and pivoted for movement in the plane of the blade to the other leg of the frame within the aperture therein to permit the front end of the blade to spring slightly in an upward direction, and a spring mounted in the leg receiving the block and pressing downwardly on said block to augment the force exerted by the springing of the blade.

6. A saw-blade holder for hacksaw machines comprising, in combination, a carrier, means for mounting the ends of a blade in the carrier and operable to place the blade under a normal predetermined tension lengthwise thereof, said means being adapted to permit a slight pivotal movement of the forward end of the blade to increase the tension of the blade as an incident to its application to a piece of work, and means for automatically augmenting the resistance to said pivotal movement due to the increased tension of the blade. 7. A saw frame for a power hack saw having, in combination with a saw blade, two blocks of substantia1 thickness each having a longitudinal slot in one end adapted to receive one end of said blade, supporting legs rigidly mounted in spaced relation and having alined apertures therein for slidably receiving the respective blocks, a screw clamp carried by the inner end of each block for clamping one end of the saw blade within the slot in the block, and means carried by the outer ends of said blocks for limiting the inward sliding movement thereof relative to said supporting legs and adapted to maintain said blade under tension, the screw clamp in each block lying wholly within the cross-sectional area of the block and being adapted to permit said block and itsscrew clamp to slide outwardly as a unit through its corresponding aperture in the event of breakage of the blade.

GEORGE J. BLUM. 

